Experts in the United States are contradicting government recommendations and warnings regarding fish and other seafood in the diets of pregnant and breast-feeding women.
The government currently advises such women to consume no more than 12 ounces of fish and other seafood weekly because it may contain trace amounts of mercury which can harm the nervous system of a fetus.
Now a group of 14 obstetricians and nutritionists say the threat of mercury poisoning is a theoretical one and the warnings have frightened many pregnant women from eating fish at all.
The group says this deprives them and their babies of vital nutrients such as omega-3 fatty acids, which are important for brain and motor skill development in children and can help prevent postpartum depression in mothers.
Their recommendations are the result of a coalition of a not-for-profit group comprised of the National Healthy Mothers, Healthy Babies Coalition, whose members include the Centers for Disease Control and Prevention, the Agriculture Department, the March of Dimes, the American College of Obstetricians and Gynecologists and others.
The coalition says while it received $60,000 from a seafood industry trade group, they defend the independence of their work and say there has never been a case of fetal mercury toxicity due to fish consumption reported in the United States.
The Healthy Mothers guidelines urge women who want to become pregnant, are pregnant or are breast-feeding to eat a minimum of 12 ounces each week of fish such as salmon, tuna, sardines and mackerel and seafood such as shrimp, lobster and clams, and does not state a recommended upper limit for consumption.
Twelve ounces equates to two to three servings a week.
One of the experts, Dr. Ashley Roman, a professor of obstetrics and Gynecology at New York University Medical Center, says some fish such as shark and swordfish have been shown to be higher in mercury and in other important trace elements and pregnant women may still might want to avoid them.
Fish is high in the mineral selenium and the experts say there is a growing body of evidence that selenium in ocean fish may also counteract the potential negative influence of mercury exposure.
Dr. Roman says the vast majority of fish present in the American diet, are generally very healthy fish.
The experts back their advice by citing a study published in February in the Lancet medical journal which found that children whose mothers ate more fish and other seafood while pregnant were more intelligent and had better developmental skills than those whose mothers ate less or none.
That study examined the children of 8,000 British women in order to determine how the children fared if their mothers ate more than 12 ounces of fish a week.
The Food and Drug Administration and U.S. Environmental Protection Agency issued their advice in 2001 and 2004 but data on the dangers posed by mercury comes from people exposed to chemical spills and no major studies have shown that mercury from food or vaccines has caused brain damage to mothers or children.
The FDA says it will study the recommendations but is not prepared to change its advice at the present time.